Please read description carefully.
Do not base your order on the picture presented.
Measurement of contrast sensitivity curve is based on six gratings at 3 contrast levels, 10%, 2.5%, and 1.2% contrast using 3 grating frequencies: 0.5 cpcm and 8 cpcm (10% level) or 0.5 cpcm and 4 cpcm (2.5 and 1.2% level).
Testing is based on finding the distance where the person is at threshold in seeing the direction of the grating lines.
Includes nomograms, instructions and recording forms.
Measures 8" (20 cm) in diameter.